The Messiest Celebrity Relationships Timelines Ever: From Blake Lively and Ryan Reynolds to Justin and Hailey and More Drama

These high-profile Hollywood relationships have some of the messiest timelines ever.

RadarOnline.com can reveal all the drama that has gone down in these celebrity romances.

Aaron Carter began dating Hilary Duff in December 2000 following his guest appearance on Lizzie McGuire.

In a 2005 appearance on The Big Idea With Donny Deutsch, Carter said their relationship started on his 13th birthday.

"I was dating her for like a year-and-a-half, then I just got a little bored, so I went and I started getting to know Lindsay (Lohan), dating Lindsay," he added.

Fans speculated they had a love triangle after Duff released her song Haters in 2002. Amid rumors about their messy relationship timeline, the A Cinderella Story actress seemingly denied the claims in a 2007 interview with People.

"We are both adults, and whatever happened, happened when we were young; it's over," said Duff.

Carter and Duff still rekindled their romance in April 2003 but ultimately called it quits a few months later due to another reported infidelity issue involving the late I'm All About You singer.

Before her passing, Naya Rivera penned her memoir Sorry Not Sorry: Dreams, Mistakes, and Growing Up, in which she detailed an alleged overlap between her relationship with Big Sean and his affair with Ariana Grande.

"On the one day that he was back in L.A., he said he didn't want to see me. But since she had a key, she let herself in to his house," Rivera wrote. "I walk in, go downstairs, and guess what little girl is sitting cross-legged on the couch listening to music? … It rhymes with 'Smariana Schmande,'" the late Glee star wrote.

Sean dated Grande after his split from Rivera, but their relationship lasted only eight months before breaking up.

"They both deeply care for each other and remain close friends. We kindly ask that the media respect their wish for privacy regarding this personal matter at this time," Sean and Grande's representatives said in a joint statement at the time.

Years after her relationship with Sean, Grande faced backlash again for allegedly hooking up with Ethan Slater while he was still married to his high school sweetheart, Lilly Jay. News about the entanglement also surfaced less than a year after he welcomed his first child with his then-wife.

Grande and Slater started working on the film adaptation of Wicked in December 2022. In July 2023, multiple news outlets revealed the Side to Side songstress and Dalton Gomez had split earlier that year.

Only days later, it was reported that Grande and Slater's relationship blossomed after he separated from Jay. The 32-year-old Tony-nominated actor also filed for divorce from his then-wife after four years of marriage, shortly after the news of his new relationship surfaced.

"(Grande's) the story, really. Not a girl's girl. My family is just collateral damage," Jay said after Grande and Slater's relationship went public.

On the other hand, some sources claimed Grande and Slater did not see each other until they both called it quits with their respective partners.

In May 2000, Billy Bob Thornton and Angelina Jolie shocked the masses when they tied the knot following their meeting on the set of Pushing Tin in 1999. The One False Move actor was still engaged to Laura Dern, who later reacted to the news about the sudden marriage.

"I left our home to work on a movie, and while I was away, my boyfriend got married, and I've never heard from him again," Dern told Talk magazine.

Thornton and Jolie filed for divorce in 2002 and finalized the filing in May 2003.

Blake Lively and Ryan Reynolds began dating in 2011 and married in September 2012. They first met on the set of Green Lantern in 2010 while they were still seeing other people: Lively was dating Penn Badgley while Reynolds was married to Scarlett Johansson.

Although the Deadpool & Wolverine actor told Jess Cagle he only started dating Lively a year after working together on the superhero film, the How to Murder Your Life author Cat Marnell alleged there was an overlap in the relationship.

"Fun fact Blake Lively and Ryan Reynolds hooked up when RR was still married to ScarJo, and holed up in a NOLA hotel room during the (Green Lantern)," the writer tweeted.

While Brad Pitt was still married to Jennifer Aniston, he sparked dating rumors with Jolie while working on 2005's Mr. and Mrs. Smith.

The infidelity rumors intensified after Pitt and Aniston divorced in the same year, though they tried to contain the buzz by releasing a joint statement upon announcing their split.

"For those who follow these sorts of things, we would like to explain that our separation is not the result of any of the speculation reported by the tabloid media. This decision is the result of much thoughtful consideration," they said.

Pitt and Jolie married in 2014, though their union ended in 2016 when the Maleficent actress filed for divorce. A judge finally signed off on their filing in December 2024 after more than eight years of legal proceedings.

Eddie Cibrian and LeAnn Rimes were married to other people – Cibrian to Brandi Glanville and Rimes to Dean Sheremet – when they filmed Northern Lights in Canada in November 2008. A few months later, extramarital affair rumors emerged, which the Sunset Beach alum denied in a statement.

"It is a fabricated story that is using random snapshots as connective tissue to create a scandalous relationship," said Cibrian.

Following their separations from their respective partners, Cibrian and Rimes gradually went public with their relationship until they eventually confirmed it.

Reflecting on the affair, Rimes told Robin Roberts: "That's just not me. What happened is not who I am, period. I do know how much I love him. So, I've always said I don't live my life with regret. I can't. You had two couples whose marriages didn't work who really stumbled upon each other and fell in love."

Cibrian and Rimes got engaged in December 2010 and tied the knot in April 2011.

In May 2021, John Mulaney and Anna Marie Tendler announced their split after nearly seven years of marriage. The same month, a source confirmed the former Saturday Night Live writer and Olivia Munn were dating, sparking infidelity rumors.

Mulaney quickly moved on with Munn, announcing she was pregnant with their first child during a September 2021 appearance on Late Night With Seth Meyers.

"I went to rehab in September, I got out in October, I moved out of my home from my ex-wife," he shared, explaining the timeline of their relationship. "Then in the spring I went to Los Angeles and met and started to date a wonderful woman named Olivia. I got into this relationship that's been really beautiful with someone incredible. And we're having a baby together."

In 2022, Hailey Bieber commented on the speculations that Justin Bieber cheated on Selena Gomez and that she "stole" him from the Emilia Pérez actress.

"When him and I started hooking up, or anything of that sort, he was not in any relationship. It's not my character to mess with someone's relationship, I was raised better than that," the model said on the Call Her Daddy podcast in 2022.

Before Justin and Hailey's September 2018 wedding, the Ghost hitmaker had an on-again, off-again relationship with Gomez from 2011 until they called it quits for good in March 2018.

While Kristen Stewart was still dating Robert Pattinson, she found herself in hot water after she was caught cheating on him with her Snow White and the Huntsman director, Rupert Sanders, in July 2012. Liberty Ross, the filmmaker's wife of 11 years, filed for divorce in January 2013 following the infidelity scandal.

Meanwhile, Stewart and Pattinson officially ended their relationship in May 2013 after more than four years of dating.